1990

7.5

2007

7.7

2009

7.7

2001

7.9

1997

7.9

2005

7.8

1985

8.3

2012

6.9

2001

7.8

2005

6.5

2001

7.8

2011

6.9

1994

8.5

2015

7.6

2012

7.3

2010

7.1

1999

7.6

2006

8.2

2009

8.2

2001

8.4